Space discharge tube stem machine



March 1, 1938. L. MARSHALL SPACE DISCHARGE TUBE STEM MACHINE Original Filed Oct. 7,. 1929 I Y R m A Patented Mar. 1, 19 38 1 r v UNITED STATES PATENT OFFICE SPACE DISCHARGE'TUBE STEM Laurence K. Marshall, Cambridge, Mass, as-

signor, by mesne assignments, to Raytheon Production Corporation, Newton, Mass, a corporation of Delaware Original applicationoctober 'z, 1929, Serial No.

398,052. Divided and this application September 10, 1934, Serial No. 743,373

9 Claims.' (01. 49-2) This invention relates to a method and means tube machines, with the exception that tour anfor manufacturing stems for vacuum tubes and vils are provided. The head comprises jaws I the like. In the manufacture of vacuum tubes and 2 which are spring-pressed, and maintain and the like, it is customary, to disposethe several between them a glass tube 3 out of which the 5 wires to be sealed in the glass in a jig and slip press is to be formed. Within the glass tube 5 a glass tube over them. The tube is then heated are a plurality of wires positioned in a jig. An to soften the glass and pressed to the desired exhaust tube 6 is suitably maintained'by wellshape. It is desirable to have a press of such known mechanism generally designated as I. shape as to permit the wires sealed therein to Handles 8 and 9 are provided for respectively 10 extend upwardly into the tube without bending, releasing jaws l and 2 and mechanism 1. Four 10 while supporting the electrode structure. This anvils I, ll, l2, and I3 are provided, and are has the advantage of eliminating the step of adapted to be actuated by arms l5. These arms bending the wires with the possibility'of resultare pivoted at 16 to the head proper, and are ant defective seals. Furthermore, heavy spring adapted to be moved by means of adjustable rods wire may be used which more effectively supports l1. These rods are suitably actuated by a spider the electrode structure against shock and vibral8 and push-rod IS in the usual manner.- tion. The stem of my invention has a plurality As shown in Fig. 2, anvils l0 and I 2 have base of wings or portions extending in more than one portions 20 from the forward faces of which vertical plane, the wings, however, not meeting project portions 2|. Anvils H and II have base I 20 at a common junction. My preferred form is portions 22 provided with sloping sides 23 and 0 H-shaped. By having a stem of such a shape, terminating in rectangular projecting portions wires may be sealed in various corners to form 24. As will be noted in Fig. 1, all anvils are of a rigid skeleton frame-work upon which the ensuitable thickness for forming thefpress. tire electrode structure of a vacuum tube may be In Fig. 3, a modification of Fig. 2 is shown in 25 supported. which the middle portion of the stem. is made 25 In order to make tight seals in the stems, it is substantially thicker. This is preferably accomessential that pressure normal to the surfaces plished by making portions 24"01 anvils II and; formed be applied. Thus in the case of the i3 of less width than in Fig. 2, resulting in a well-known fiat press, anvils press the glass from greater distance between anvils when the press opposite sides. Each one for-ms a reacting block is formed. 3 for the other, and pressure on the glass is-applied It is evident that supporting arbors may be perpendicularly thereto. Presses ofcomplex sealed in any desired portions of either one of shape may be manufactured by different meththe stems. ods and with difierently shaped anvils. With In actual manufacture, it has been found that such a number of possible ways and means, it stems of this type can be made very easily with- 5 is clear that the best must include the above out any unusual number of-defective seals. As fundamentals. is well known, in order to have the wires sealed In my method of making the stem, I have four into the glass perfectly, it is necessary that the anvils pressed toward each other, each opposite soft glass be firmly pressed to the wire. It is 40 pair being in line. v The forward facesof each obvious that from the shape of the anvils the 40 anvil apply pressure to the soft glass. The faces central pinch 3| or 3| will be firmly pressed by of two anvils react against each other as in the portions 24 or 24"of anvils II and I3. Furtherordinary fiat press method. In addition, the more, anvils l0 and I2 press end portions of 32 sides of these twoanvils form reaction surfaces while pressing the'connecting intermediate pinch for the remaining two anvils. In this way, firm transversely. Because of the flaring sides 23 of 45 pressure normal to the resulting surfaces is apanvils It and 13, the end portions of wings 32 plied substantially over the press. 7 are firmly pressed against the corresponding Referring to the drawing, Fig. 1 is a perspecwires to seal them into place. tive view of a head for making my press; The presses shown in Figs. 2 and 3, while use- F 2 is a diagrammatic view-showing the f ul with anyelectrode structure, are especially50 n sp s a s em; and useful for supporting the electrode structures l.=ig. 3 is similar to Fig. 2, except that a modified shown in the copending applications of Andrew form of stem is shown. E. Lyle, Serial No. 315,275, filed October 26, 1928,

Referring to the drawing, the head shown in Serial No. 336,243, filed January 30, 1929, Serial I Fig. 1 is ofthe' usual typeprovided on vacuum, N0. 381.018.'filed July 25, 1929, and the patent to 55 Paul T. Weeks, No. 1,961,269, dated June 5, 1934.

It is evident that the press need not have the two end portions at right angles to the intermediate pinch portion to form an H, but may be at any desired angle. Furthermore, by changing the dimensions of the anvils, any desired size of press having any desired thickness of the various wing portions may be had.If desired, one of the end, wing portions 32 may be omitted and a T-sha-ped press be formed instead. For certain electrode structures, this may be found desirable.

This application is a division of my co-pending application, Serial No. 398,052, filed October '7, 1929.

What is claimed is:

1. A head for forming a press includingfour anvils, two opposing anvils having flat faces adapted to press against the glass, said tworemaining anvils having flat forwardjfaces and flaring sides. v

2. In a head for making a press, a plurality of pairs of opposing anvils, said anvils having suitable faces for pressing against the glass, one pair of said anvils adapted to approach nearer to-each other than the remaining anvils and to function as supporting means for the portion of the glass adaptedto be pressed by said remaining anvils.

3. A stein-making machine comprising means for supporting a plurality of stem wires in a plurality of planes, means for supporting a glass tube from which the stemis to be formed around said wires, a pair of movable anvils for pressing the glass, said anvils being movable in a plane substantially at right angles to one of said 'first--' named planes, a second pair of movable anvils for pressing said glass, said second pair of anvils being movable in a plane substantially at right angles to another of said first-named planes.

. 4. A stem-making machine comprising means for supporting a plurality of stem wires in a plurality. of planes, means for supporting a glass tube from which the stem is to be formed around said wires, a pair of movable anvils for pressing the glass, said anvils being movablein a plane substantially at right angles to one of said first named planes, a second pair of movable anvils for pressing said glass, said second pair of anvils being movable in a plane substantially at right angles to another of said first-named planes, the planes. in which said anvils move intersecting substantially at the center of the press to be formed, said anvils being movable in said planes toward said intersection.

5. A stem-making machine comprising means for supporting a plurality of-stern wires in a plurality of planes, means for supporting a glass tube from which the stem is to be formed around said wires, a pair of movable anvils for pressing the glass, said anvils being movable in a plane substantially at right angles to one of said firstnamed planes, the opposed faces of said anvil pair of said anvils of said second pair reacting against the sides of the anvils of said first pair to press the glass between said faces and said sides-to form additional presses in another of said planes.

6. A stem-making machine comprising means for holding a plurality of wiresin substantially the same plane, means for holding a plurality of wires in a plane transverse to said first-mentioned wires, pressing means for forming a seal around said wires, said pressing means comprising a pair of pressing anvils movable in a direction substantially perpendicular to said first-mentioned wires, and a second pressing anvil movable in a direction substantially perpendicular to said second-mentioned wires.

7. A stem-making machine comprising means for holding a plurality of wires in substantially the same plane, means for holding a plurality of wires in a plane transverse to said first-mentioned wires, pressing means for forming a seal around said wires, said pressing means comprising a pair of pressing anvils movable in a direction substantially perpendicular to said firstmentioned wires, and a second pressing anvil movable in a direction substantially perpendicular to said second-mentioned wires at one end of the row of said first-mentioned wires.

8. A stem-making machine comprising means for holding a plurality of wires in substantially the same plane, means for holding a plurality of wires in a plane transverse to said first-mentioned wires, pressing means for forming a seal around said wires, said pressing means comprising a pair of pressing anvils movable in a direction substantially perpendicular to said first-mentioned wires, a second pressing anvil movable in a direction substantially perpendicular to said secondmentioned wires, and means for supporting a tube 'from which the stem is to be formed around positionto be engaged by said otally mounted on said supporting member, an

additional anvil pivotally mounted on said supporting member, and means for bringing said anvils into pressing engagement with said tube, said additional anvil in its pressing position laterally overlying said pair of anvils.

LAURENCE K. MARSHALL. 

